Generally though it becomes easy to apply joint locks when someone is resisting if the person doing the technique has enough knowledge of how to disrupt balance, move while keeping one's own balance and use the pull, push or turn of the subject to help in disrupting balance, allowing for whichever technique is most applicable based on the resisting motion.

Most folks who get problems trying joint locks on resistant folks experience it because they have failed to first distract the mental/physical structure with something like a balance breaking movement, strike etc.